nesting problem: difference in bathymetry

26 views
Skip to first unread message

Luana F. Bueno

unread,
Jul 5, 2022, 11:11:31 AMJul 5
to HYCOM.org Forum
Hi Alan,

I hope you are fine. I have some doubts about the restart file and the boundary conditions that I would like to ask you about it.

I am nesting my regional model of 1/36 resolution in a 1/12 global model. Both models have the same vertical structure (number of layers), however their bathymetries are different. I did the merge bathymetry considering 19 points, since my grid is IDM(741)xJDM(920), following from 1.0 (19) to 0.1 (1). Is this merge bathymetry enough to deal with the problem of bathymetry difference in the buffer zone? I am asking that because what I have seen is that when the bathymetry of the regional model is deeper than the bathymetry of the global model, it gives a negative dp. 

Besides that, when creating a restart file using an archv from the global model it carries the bathymetry of this model and not the bathymetry of my model that goes for example in the layers structure of the climatological restart used as the model input restart file. Shouldn't it follows the bathymetry that I gave when creating the restart file? Because it will give negative dp already in the first step.

I am confused about nesting models with different bathymetry because it seens that it will always follow the original bathymtry of the global model despite informing the bathymetry of my model.

I appreciate so much your help.
Best regards,
Luana Bueno


Alan Wallcraft

unread,
Jul 6, 2022, 9:22:23 AMJul 6
to HYCOM.org Forum, lufer...@hotmail.com
See GOMb0.08 or how to set-up a regional configuration nested in a global domain The bathymeyrty must be interpolated from the coarse depths and coastline in the buffer zone (where nest_rmu is non-zero), a combination "near" the buffer zone, and the fine depths and coastline everywhere else (step 1d). Note that there must be land behind the open boundary in the model bathymetry, but the nest files must be made with sea behind the open boundary (step 1b). Note that this works because the model bathymetry is the same as this bathymetry everywhere that the nested archive is used.

As you say, when creating the archive file that becomes the restart file, you need to use the find grid model bathymetry (that you created in step 1d).  This is covered in 5-D (How to create a restart file from the GLBb0.08 suitable for GOMb0.08) step b.

Alan.
Reply all
Reply to author
Forward
0 new messages